(a) Field of the Invention
The present invention relates to a thin film transistor substrate for a liquid crystal display and a method for repairing the substrate.
(b) Description of the Related Art
Liquid crystal displays are at present the most commonly used flat panel displays. The liquid crystal display (LCD) is structured to have liquid crystal material injected between two substrates. A voltage of a different potential is applied to electrodes of the substrates to form an electric field such that the alignment of liquid crystal molecules of the liquid crystal material changes. Accordingly, the transmittance of incident light is controlled to enable the display of images.
Among the different types of LCDs, the thin film transistor (TFT) LCD is the most typically applied configuration. In the TFT-LCD, thin film transistors and pixel electrodes are formed on one of the two substrates, and a color filter, a black matrix and a common electrode are formed on the other substrate, with the common electrode being formed over an entire surface of this substrate. The thin film transistors switch the voltage applied to the electrodes of the substrates.
To improve the brightness of the TFT-LCD, a high aperture ratio of the substrates must be obtained. However, the black matrix with a large width in order to compensate for differences in alignment of the two substrates reduces the aperture ratio.
The present invention has been made in an effort to solve the above problems.
It is an object of the present invention to provide a thin film transistor substrate for a liquid crystal display and a method for repairing the substrate, in which a high aperture ratio of the liquid crystal display is ensured.
To achieve the above object, the present invention provides a thin film transistor substrate for a liquid crystal display and a method for repairing the substrate. The thin film transistor substrate for a liquid crystal display comprises an insulating substrate; a black matrix formed on the insulating substrate having apertures in areas of pixels, which are provided in a matrix, such that the black matrix resembles a net; an insulating layer covering the black matrix; gate wiring formed on the insulating layer, the gate wiring including gate lines extended in a first direction across the substrate and gate electrodes connected to the gate lines; a gate insulating layer formed over the gate wiring; a semiconductor layer formed over the gate insulating layer; an ohmic contact layer formed over the semiconductor layer; data wiring including source electrodes and drain electrodes formed separated from each other over the ohmic contact layer, and data lines connected to the source electrodes and crossing the gate lines to define pixels; a protection layer formed over the data wiring; and pixel electrodes electrically connected to the drain electrodes.
According to a feature of the present invention, the substrate further comprises a buffer layer formed on the same layer as the gate wiring and the data wiring, the buffer layer being formed between portions of the black matrix.
According to another feature of the present invention, the black matrix includes first portions overlapping the gate lines, and second portions separated from the first portions and overlapping the data lines.
According to yet another feature of the present invention, a portion of the black matrix overlapping the gate wiring or the data wiring is removed.
According to still yet another feature of the present invention, the black matrix is formed overlapping adjacent pixel electrodes.
According to still yet another feature of the present invention, a width of overlapping of the pixel electrodes and the black matrix is in the range of 0.5-2 xcexcm.
According to still yet another feature of the present invention, the pixel electrodes and the data lines are spaced apart at a distance in the range of 2-6 xcexcm.
According to still yet another feature of the present invention, the insulating layer contains silicon oxide.
According to still yet another feature of the present invention, the insulating layer is formed at a thickness of 0.5-3 xcexcm.
According to still yet another feature of the present invention, the substrate is used in a vertically-aligned liquid crystal display, in which liquid crystal molecules are aligned vertically to the substrate.
According to still yet another feature of the present invention, liquid crystal molecules are aligned parallel to the substrate and the pixel electrodes are formed linearly, and it further comprises a linear common electrode opposing the pixel electrodes.
According to still yet another feature of the present invention, the substrate further comprises storage electrodes overlapping the pixel electrodes to form a storage capacitance.
The method for repairing a thin film transistor substrate for a liquid crystal display comprises the step of shorting the disconnected gate line and the first portion matrix or the disconnected data line and the second portion of the black matrix.
A liquid crystal display comprises an insulating first substrate; a black matrix formed on the insulating substrate having apertures in areas of pixels, which are provided in a matrix, such that the black matrix resembles a net; an insulating layer covering the black matrix; gate wiring formed on the insulating layer, the gate wiring including gate lines extended in a first direction across the substrate and gate electrodes connected to the gate lines; a gate insulating layer formed over the gate wiring; a semiconductor layer formed over the gate insulating layer; an ohmic contact layer formed over the semiconductor layer; data wiring including source electrodes and drain electrodes formed separated from each other over the ohmic contact layer, and data lines connected to the source electrodes and crossing the gate lines to define pixels; a protection layer formed over the data wiring; pixel wiring including pixel electrodes electrically connected to the drain electrodes through contact holes of the protection layer; an insulating second substrate provided opposing the first substrate; and a common electrode formed on the second substrate, the common electrode opposing the pixel electrodes to form an electric field for driving liquid crystal molecules.
According to a feature of the present invention, the liquid crystal display further comprises a buffer layer formed on the same layer as the gate wiring and the data wiring, the buffer layer being formed between portions of the black matrix.
According to another feature of the present invention, the black matrix includes first portions overlapping the gate lines, and second portions separated from the first portions and overlapping the data lines.
According to yet another feature of the present invention, the liquid crystal molecules are aligned vertically to the first and second substrates.
According to still yet another feature of the present invention, the pixel electrodes include one or more aperture patterns to disperse a slanting direction of the liquid crystal molecules such that the liquid crystal molecules are aligned in different directions.
According to still yet another feature of the present invention, the common electrode includes one or more aperture patterns to disperse a slanting direction of the liquid crystal molecules such that the liquid crystal molecules are aligned in different directions.
According to still yet another feature of the present invention, the aperture patterns align the liquid crystal molecules into four different directions.
According to still yet another feature of the present invention, the liquid crystal display further comprises storage electrodes overlapping the pixel electrodes to form a storage capacitance.
According to still yet another feature of the present invention, the liquid crystal display further comprises a light-blocking layer formed in a center portion of the aperture patterns or at areas corresponding to edges of the aperture patterns.